A header for an agricultural harvester including an epicyclical drive gear train operatively connected to a first cutter bar, an epicyclical driven gear train operatively connected to a second cutter bar, and a shaft extending between and operatively connected to the epicyclical drive gear train and the epicyclical driven gear train. The epicyclical drive gear train rotates in a first direction and the shaft is configured to rotate the epicyclical driven gear train in a second direction opposite the first direction or in the same direction as the first direction. Each of the epicyclical drive gear train and epicyclical driven gear train includes a bevel gear for operatively engaging bevel gears on the shaft. Operation of the epicyclical drive gear train and epicyclical driven gear train results in substantially linear oscillating motion of the cutter bars.